this trait as originating in the theoretical heritage they have brought to the problem. It has caused many of them to fail to ask whether reality conforms to this preconception.
Migrants to large cities, on an overall basis, are positively selective in relation to the populations from which they originate. (Whether they are also positively selective to small or medium-size cities is an intriguing question, but the evidence is so slight that no conclusion can be reached at this time.) The forms of selectivity (age, education, occupation, risk-taking propensity, etc.) are interrelated and reinforce one another. It was argued earlier in this paper that the allegations (they seldom had more substance than this) of personal and social disorganization in the large cities were exaggerated. If my thesis of positive selectivity is sound, it follows that the migrants, on the average, will be better equipped to cope with conditions in the city.
Although migration to large cities has been found to be positively selective, there are additional questions to be posed as to whether selectivity is changing and, if so, in what direction. Unfortunately, the evidence on these matters is meager. The Monterrey data indicate a clear decline in migrant selectivity over a generation, but we cannot be sure that this holds for other large Mexican cities, let alone cities in other world regions. I think it is safe to assume that if a rapid rate of urbanization is sustained over several decades, selectivity will be lower at the end than the beginning of the period, but this still leaves unanswered questions about the extent and form of this change. In any event, declining selectivity has a host of implications, especially its effects on the city of destination. It suggests that accommodation into the occupational and social structure of the city will become more rather than less of a problem, even though the proportion of the total population represented by migrants steadily declines.
Migrant Selectivity, the Growth of Large Cities, and Economic Development
It should be evident by now that I am more positive than some about the urbanization process in developing countries. In particular the thrust of this paper has been to show the connection between migrant selectivity and the growth of large cities. It is difficult to deny that massive population redistribution is an inherent part of the developmental process, nor that urbanization, as a prominent feature of this redistribution, requires much migration. Large cities draw migrants from other urban centers and from rural areas. As economists often view migration favorably because of its consequences for labor mobility, so can sociologists view it favorably. Blau and Duncan see migration as expanding the life chances available to men. Their conclusion, based upon their investigation of the occupational mobility in the United States, would seem equally appropriate for other societies.iterature. A number of social scientists have seen the migration process through a glass all-too-darkly. I have tried to explain the group who must make the (rreatest adjustment in stvlp. of livino nnH tVip.rpfnrp nrp nrp«nmali1\/ m^et inhe predominantly male rural-urban migration, in the multilingual character of the society, in the existence of polygamy, and